The present disclosure generally relates to trench structures, such as trench capacitors. More particularly, the present disclosure relates to memory devices including trench capacitors.
Embedded (dynamic random access memory (DRAM) devices may include trench capacitors. A trench capacitor is a three dimensional device that can be formed by etching a trench into a semiconductor substrate. After trench etching, a buried plate electrode, also referred to as a diffusion plate, is typically formed about the exterior portion of the trench and a node dielectric is then formed on the inner walls of the trench. Next, the trench can be filled, for example, with doped polysilicon, such as N-type polycrystalline silicon (“N-type Poly-Si”). The doped poly-Si serves as one electrode of the capacitor, often referred to as the upper electrode or storage node, and the buried plate electrode serves as a second electrode of the capacitor, often referred to as the lower electrode. The node dielectric separates the buried plate and the upper electrode, and serves as the insulating layer of the trench capacitor.